Controller system for pool and/or spa

ABSTRACT

A control system for a pool and spa. Main line voltage is provided through a single line voltage service and a single ground fault circuit interrupter circuit, facilitating a ground fault test and simplifying installation. The control system acts as a power distribution system for controlling the pool and spa equipment, with a circuit board assembly including individual fuse protection devices and switching circuits. A test algorithm is included, wherein the control system is disabled from normal operation if the GFCI test fails. The pool operator manually enters a water fill command, and the controller system automatically opens the fill valve for a predetermined time interval, and then automatically closes the valve. An emergency disconnect switch is mounted near the bathing area, connected by low voltage wiring to the controller system cabinet. The controller system senses the emergency switch closure and disconnects line voltage to the line voltage loads. The emergency switch closure also remotely induces a ground fault, tripping the GFCI. A sensing circuit allows the controller system to sense the presence of the emergency switch system, and issues a warning and prevents normal operation of the pool and spa system if not connected. A gas pressure sensor monitors the natural gas line, and the heater is disabled and a warning given under low pressure conditions. Abnormal filter backpressure triggers a warning when the filter needs service. A temperature sensor has parallel sensing elements in a common housing to provide separate sensing circuits.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from application Ser. No. 10/860,392,filed Jun. 1, 2004, which in turn was a divisional application ofapplication Ser. No. 10/066,868, filed Feb. 4, 2002, which in turn was adivision of application Ser. No. 09/451,561, filed Nov. 30, 1999, nowU.S. Pat. No. 6,407,469, the entire contents of which applications areincorporated herein by this reference.

BACKGROUND

Electronic control systems have been employed to control variousfunctions. Typically, however, the power hookups for the differentcomponents associated with the pool or spa have been run directlythrough circuit breakers in a main or auxiliary panel to the variouscomponents, such as the pump, heater and lights. This is a timeconsuming task, and one which can lead to wiring mistakes, in view ofthe number of wiring connections which need to be made. There istherefore a need to simplify the power hookups to the variouscomponents, in order to control costs and provide more reliableinstallations.

A problem with pools is maintaining the level of water within the pool.Evaporation losses can be significant, and so it is advantageous to havean automated system for keeping the water level at a given desiredlevel. Stand alone systems for doing this are known, but tend to besomewhat complex. It would be advantageous to integrate such a systemwith the pool controller, for reliability, ease of installation and costsavings.

Emergency shutoff switches are typically mounted close to the spa, toenable quick shutoff of pumps and other functions in an emergency. Itwould be an advantage to provide an electrical shutoff switch which didnot require high power connections to the switch, and whose installationcould be verified by the controller.

Ground fault circuit interruption devices are typically employed in pooland spa controls. It would be an advantage to provide a technique fortesting for proper operation and installation of these circuits.

The pool plumbing system typically includes a filter system for removingparticulates from the pool or spa water. These commonly use diatomaceousearth or other filtering agents. As the filter becomes filled withparticulates removed from the water, the filter back pressure rises, andultimately for proper operation the filter must be cleaned, e.g. bybackflushing the filter. Presently, a sight pressure gauge is mounted onthe filter, so that the pool maintenance technician can visually checkthe back pressure status. It would improve the maintenance of the filteroperation to automate the pressure reading.

The water circulation system for the pool/spa also includes a heater forwarming the pool and/or spa water for the user's comfort. This heater istypically gas-operated, and does not operate properly when the gaspressure is too low. It would therefore improve the reliability andoperation of the water circulation system if a technique could be foundto monitor the gas pressure and provide a message and/or control signalsin the event of a low gas pressure condition.

Power loads imposed by the pool system's electrical components can beconsiderable. Techniques for efficiently using the power load rating ofthe control system are therefore needed.

BRIEF DESCRIPTION OF THE DRAWING

These and other features and advantages of the present invention willbecome more apparent from the following detailed description of anexemplary embodiment thereof, as illustrated in the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic view of a pool and spa system utilizing aspectsof this invention.

FIG. 2 is a simplified block diagram of elements of a pool servicesystem embodying this invention.

FIG. 3 illustrates a control panel cabinet for housing the poolcontroller and power distribution system of the pool service system, andthe service control panel mounted on the cabinet.

FIG. 4 is a diagrammatic view of the pool control panel comprising thesystem of FIG. 2.

FIG. 5 is a diagrammatic view of the spa control panel comprising thesystem of FIG. 2.

FIG. 6 is a detailed block diagram of the pool service of FIG. 2.

FIG. 7 is a top view illustrating a portion of the multilayer conductivetrace pattern of the controller circuit board.

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7.

FIG. 9 is an isometric view of the connector terminal block used in thecontrol cabinet for connecting line voltage wiring.

FIG. 10 is a top view of the control cabinet of FIG. 3, which the coverin a open position illustrate the controller circuit board and linevoltage and low voltage connections, and the main compartment bay andthe two side compartments through which low voltage wiring is passed.

FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10.

FIG. 12 is a cross-sectional view taken along line 12-12 of FIG. 10.

FIG. 13 is a schematic diagram of a simplified pool service system inaccordance with the invention.

FIGS. 14A-14F are simplified flow diagrams illustrating salient programfeatures of the controller comprising the system of FIG. 2.

FIG. 15 is a simplified schematic diagram illustrating the GFCI testcircuit comprising the system of FIG. 2.

FIG. 16 is a schematic diagram of an emergency disconnect switch inaccordance with an aspect of the invention.

FIG. 17 is a schematic diagram of a temperature sensor in accordancewith an aspect of the invention.

FIG. 18 is a diagrammatic view of the temperature sensor of FIG. 17.

FIG. 19 is a bottom view of the circuit board comprising the temperaturesensor of FIG. 17.

FIGS. 20A-20C are circuit schematics of an exemplary embodiment of acontroller board comprising the system of FIG. 2.

FIG. 21 illustrates connection of two 120 Amp line voltage loads using a240 VAC 50 Amp service.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a diagrammatic view of a pool and spa system utilizing aspectsof this invention. In this embodiment, the pool 1 and spa 2 share filter77 and heater 78 through a plumbing arrangement including three-wayvalves 70 and 72, although other arrangements can be employed, such asseparate heaters and filters for the pool 1 and spa 2. A conventionalskimmer 3 is included, and its drain line 7 and the pool drain line 6are joined at a junction tee before connection to one input of the valve70. The drain line 5 from the spa is connected to the other input ofvalve 70. The valve output is connected to the input side of the filterpump 80 through water line 8. A water line 9 runs from the pump outputto the filter input. The filter output is connected by water line 10 tothe heater input. The heater output 11 is connected to the input of thethree-way valve 72. One output of the valve is connected to water line12 leading to a pool inlet. The other output of valve 72 is connected towater line 13 leading to a spa inlet.

The system includes pool and spa lights 90A, yard lights 90B, and adecorative fiber optic lighting system 88 typically mounted along thepool coping.

To the extent just described, the pool and spa system is conventional.In accordance with aspects of the invention, a controller and powerdistribution system 100 is provided, which controls operation of thesystem 50, and which receives AC line voltage service, and distributesline voltage to the line voltage loads, including the heater, pump,lights and fiber optic lighting. The controller 100 further controls theoperation of the line voltage loads, and the valves 70 and 72. Moreover,the controller 100 receives input data from a variety of sensors,including a gate open alarm 218, a pool cover alarm 216, water pressuresensors 208A (filter input pressure) and 208B (filter output pressure),gas pressure 224 for the gas supply line 15 to the heater, temperaturesensor 204 (temperature of water entering the heater), temperaturesensor 206 (temperature of water leaving the heater), and water ph andoxygen reduction potential (ORP) sensors 212 and 214 in the water line8. A master control panel 102 is coupled to the controller 100 forproviding a display and command and data input device by which thesystem 100 communicates with a user. The locations of the varioussensors may vary depending on the installation. For example, the watertemperature sensor 204 may alternatively be placed at the inlet to thepump 80, in the water line between the valve 70 and the pump 80.

FIG. 2 is a simplified block diagram of a pool service system 50embodying this invention. This embodiment will be described in thecontext of a residential pool with spa as illustrated in FIG. 1,although it is to be understood that the system can be utilized withlarger pool installations, such as hotel/motel pool systems and thelike. The system includes the controller and power distribution system100, which receives AC line power from the main or sub line voltagedistribution panel 102. In this example, the panel 102 supplies 50 Ampservice on line voltage wiring 60A, which is connected to a ground faultcircuit interrupter (GFCI) circuit 62, and then through line voltagewiring 60B to the controller and power distribution system 100. As willbe described in further detail below, the system 100 distributes linevoltage power to various line voltage loads, and also includes a lowvoltage transforming function to provide low voltage AC and DC power atvarious low voltages need by the electronic devices and low voltageloads.

In contrast to prior techniques for wiring up pool equipment, the mainline voltage power is provided through a single main line voltageservice connection 60A, 60B and GFCI 62 to system 100, rather thanthrough a plurality of line voltage service connections each with itsown GFCI circuit and circuit breaker circuit. This simplifies the wiringeffort and labor involved in a new installation. The system 100 is notlimited to the 50 Amp main line service, and can include auxiliary lineservices 64 and 66, which can be used to power auxiliary loads throughconventional circuit breaker-protected connections. Typically theseauxiliary connections are made on auxiliary circuit boards mounted inthe control cabinet.

The system 50 will typically also include the master pool control panel102 as well as a spa control panel 104. The pool control panel can belocated inside the residence, adjacent a door leading out to the pool,or in other locations convenient for the user. The pool control panelcould also be installed on the cover of the controller cabinet 112. Thespa control panel 104 is typically located adjacent the spa forconvenient access by spa users.

FIG. 3 illustrates a control panel cabinet 110 for housing the system100, and which also includes a service control panel 112, which includesseveral touch switches 112A and status indicator lights 112B. Techniquesfor constructing a suitable control panel are described in U.S. Pat. No.5,332,944. The switches permit user commands to be entered at thecabinet 110. If the pool control panel is mounted on the cover of thecabinet 110, the service panel would be omitted. The service panel 112in this exemplary embodiment includes eight manually actuated controlswitches/buttons. These are used to turn on or enable the filter pump,the pool and spa lights, the heater, and five auxiliary buttons whichcan be used for such features as the cleaner pump, yard lights, anauxiliary valve, a fiber optic decorative lighting system and anauxiliary pump. The service panel is located on the exterior of thehinged lockable cover for the cabinet 110, and is fully water resistant.This mounting provides a significant safety benefit, since the poolservice professional or homeowner does not need to open the systemcabinet 112, exposing line voltage wiring, in order to do routine poolmaintenance.

FIG. 4 illustrates the master control panel 102, which in this exemplaryembodiment includes an LCD or other display 102A, panel switches 102Band indicator lights 102C. This panel 102 includes a display fordisplaying to the operator various status information and messages, andcontrols which permit the operator to enter commands or input data tothe system 100. The switches accept user commands and inputs, toinitiate system actions or enter information into the controller 100.For example, the switches or buttons can include up and down buttons fortemperature control and programming, a filter button for activating thefilter pump, a light button for controlling the pool and spa lights, aspa button which controls the valves 70 and 72, turns on the spa jetpump, and turns off the cleaner pump if the system is so equipped, aheater enable button to enable operation of the heater, a program buttonto put the system in a programming mode, and five auxiliary buttonswhich can be used for such features as the cleaner pump, yard lights, anauxiliary valve, a fiber optic decorative lighting system and anauxiliary pump.

FIG. 5 is a similar view of the spa control panel 104, which alsoincludes an LCD or other display 104A, panel switches/buttons 104B andindicator lights 104C, which accepts user commands and inputs, toinitiate systems actions or enter information into the controller 100.In an exemplary embodiment, there are four buttons, one button fortemperature control, one button to control the spa jets (valves andfilter pump) and an optional jet pump, a spa light button, and anauxiliary button. The panel 104 is mounted in or near the spa 2, abovethe water line. A low voltage cable runs from the panel to thecontroller system 100.

FIG. 6 is a schematic block diagram of the pool service system 50. Theservice system includes a number of components which require electricalpower for operation and/or control. In accordance with an aspect of thisinvention, the electrical power at line voltage is routed through a poolcontroller and power distribution system 100. Primary electrical poweris by the 50 Amp primary service 60 from the main panel or 100 Amp subpanel 40. Of course, the particular ampere ratings for the circuits ofthis system are merely exemplary, and could be varied in accordance withthe demands of particular applications. The primary service 60 isprovided with a ground fault continuity interrupt (GFCI) circuit 62, toprovide ground fault protection for the primary power service to thesystem. Auxiliary electrical power service is provided in this exampleby a 20 Amp service line 64 and a 30 Amp service line 66, although theauxiliary service can be omitted for many applications.

The primary line voltage service 60 is provided by a 240 VAC line feed,comprising in a typical installation a neutral conductor, a groundconductor, a first voltage phase conductor and a second voltage phaseconductor. These conductors are conventionally color coded, so thataccording to the coding convention, the ground conductor has greeninsulation, the neutral conductor has white insulation, the firstvoltage phase conductor has black insulation and the second voltagephase conductor has red insulation. The black conductor has a firstpolarity phase with respect to the neutral conductor, and the redconductor has a second polarity phase with respect to the neutralconductor, and 180 degrees different from the phase of the firstpolarity phase, such that 120 VAC is developed between the neutral andthe black conductors, 120 VAC is developed between the neutral and thered conductors, and 240 VAC is developed between the black and the redconductors. In the embodiments described below, the 50 Amp service 60Bincludes red conductor 60B1, black conductor 60B2, white (neutral)conductor 60B3, and green (ground) conductor 60B4 (see FIG. 9).

Various components which are controlled and/or receive electricaloperating power through the system 100 are shown in FIG. 6. Thesecomponents can include the valves 70, 72, 74, the pool fill spout valve76, the pool water heater 78, the filter pump 80, the cleaner pump 82,an auxiliary pump 84, a spa jet pump 86, the decorative fiber opticsystem 88, lighting system 90, spa blower 92 and auxiliary lights 94.The foregoing particular components is an illustrative listing; for anygiven pool installation, some of the components will be omitted, andother components may be added, all depending on the design of theparticular installation.

The pool controller 100 receives input data signals from various sensorsand input sources. These include several temperature sensors, the airtemperature sensor 202 for providing ambient air temperature, the watertemperature sensor 204 for providing the temperature of the water at theinput to the heater, and the water temperature 206 for providing thetemperature of the water at the output of the heater. Other sensorsinclude the filter backpressure sensor system 208 comprising pressuresensors 208A and 208B, ORP sensor 210, pH sensor 212, water level sensor214 for providing a pool water level indication, a “cover off” sensor216, a “gate locked” sensor 218, a solar sensor 220 for detecting thetemperature at a solar heater, and an emergency stop switch 350, to bedescribed in greater detail below. As is known in the art, thecontroller can respond to the solar temperature, to actuate a valve todivert water to pass through a solar heater, if the installation is soequipped, instead of through the gas water heater. The water levelsensor for example can include a probe which extends into an area atwhich the water level will reach at a desired fill level, and sense thepresence or absence of water at this level.

In accordance with an aspect of the invention, a direct 50 Amp linepower connection is made between the main panel 40 for the residencedirectly to the pool controller and distribution system 100, through the50 Amp GFCI circuit 62. The system 100 has thereon the necessaryterminal connections for direct connection of the line voltage serviceconductors (black, red, white, green) for the 50 Amp service. Circuitprotection for the various devices such as the heater 78, filter pump80, cleaner pump 82 and auxiliary pump 84 is provided by circuitprotection devices, e.g. fuses, mounted on the pool controller circuitboard in the pool controller cabinet. This results in substantialsavings and cost and in assembly time and effort.

A typical power connection in accordance with this aspect of theinvention is illustrated in FIGS. 8-12. To facilitate the connection ofpower to the controller board, an insulating terminal block 240 isemployed within the controller cabinet 110, which carries pressureconnectors 242 and 24 to which the red and black line voltage conductorsare attached. The connectors 242, 244 each include a frame 242B, 244Binto which the end of the respective line voltage conductor is inserted.A threaded device such as set screw 242C, 244C is then advanced into theframe, capturing the end of the line voltage conductor in the frame by apressure connection.

The terminal block body 240A is fabricated of an electrically insulatingmaterial, i.e. a dielectric, and is mounted to the floor of the cabinet.The terminal block includes mounting surfaces which receive threadedfasteners 251 to secure the controller circuit board to the terminalblock, and through pressure contact, make electrical contact with thered and black line voltage connectors. An upstanding wall portion 240Bprotrudes upwardly, through a slot 250A formed in the edge of thecircuit board 250. The wall portion 240B registers the position of theterminal block in relation to the circuit board, and also physicallyprovides dielectric isolation between the line voltages carried by theconnectors 242 and 244 carry.

Conductive traces on the circuit board 250 contact respective linevoltage connector surfaces 242A and 244A (FIG. 9) of the connectors 242and 244 to provide electrical continuity between the circuit boardtraces and the red and black line voltage conductors. Representativecircuit board traces are shown in FIGS. 7 and 8.

FIG. 7 is a simplified bottom view of the circuit board 250, andillustrates printed wiring conductor patterns for carrying line voltageat 120V, at the respective first phase and the second phase. Circuittrace 252 is connected to the red wiring connector 242, and includes pad252A exposed on the bottom surface 250B of the board, for contactingconnector surface 242A upon assembly of the board to the terminal block240.

In this embodiment, the circuit board 250 is a multiple-layer structure,with conductor traces formed on the top surface, the bottom surface andin a buried intermediate layer, using known photolithographictechniques, with conductive vias interconnecting the circuit traces onthe different layers as required to form the desired circuit. Thecircuit trace 252 is mostly formed in the buried layer, and is shown inphantom lines in FIG. 7. Thus, the circuit trace pattern 252 isgenerally a buried layer, except for conductive pad 252A formed on thebottom surface 250B. The trace pattern 252 then transitions through aconductive via to a buried layer, sandwiched between layers ofdielectric comprising the board 250. This is shown in thecross-sectional view of FIG. 8, wherein trace 252 is sandwiched betweenboard dielectric layers 250C and 250D. The circuit trace 254, connectedto the black conductor 60B3 through connector 244, is a surface tracepattern, and is shown in solid line in FIG. 7.

The circuit board 250 thus includes layers of printed wiring patterns,which route the line voltage and low voltage signals to respectivedevices mounted on the board, and to the connectors to which areconnected wiring running to the line voltage loads and low voltagedevices. By use of this circuit board arrangement, the labor involved inwiring a given installation is substantially reduced, and the circuitboard can be easily removed for servicing, if necessary.

To facilitate the safe routing and separation of low voltage conductorsfrom high voltage conductors, the cabinet 110 for the system 100 isseparated into three compartments or bays, two low voltage compartments110J and 110K on either side of the middle compartment 110I. The cabinet110 in this embodiment is a metal housing structure having a hingedcover 110A, side walls 110B-110E and floor 110F. Interior metal wallpartitions 116G and 110H of the cabinet define the three compartments.All line voltage wiring enters the cabinet at the bottom wall throughholes formed in wall 110B, and remain in the main compartment. The endsof the line voltage wiring are captured in pressure connectors,including the connectors 242, 244. Pressure connectors suitable for thepurpose are commercially available, e.g., a pressure connector marketedby Connector Mfg. Co. of Alabama, Grenville, Ala., as part number CA-66.Low voltage wiring is brought from the main compartment through openingsin the side walls and through wall 110B at openings in the sidecompartments. This results in improved safety, since any failure ofinsulation on a line voltage line could cause a dangerous voltage on thelow voltage lines.

FIG. 13 is a simplified wiring diagram for an exemplary pool and spainstallation. For some installations, not all sensors and controlleddevices may be needed or desired by the owner, and the system shown inFIG. 13 does not explicitly show the identical complement of controlleddevices and sensors as shown for the system of FIG. 6. It iscontemplated that the same controller circuit board will be used in thisinstallation as well as in the system shown in FIG. 6. The exemplaryinstallation of FIG. 13 includes controlled valves 70 and 72, airtemperature sensor 202, water temperature sensor 204 which measures thetemperature at the inlet to the heater, which should be the same as thewater temperature in the pool or spa, spa jet pump 86, filter pump 80,water heater 78, spa lights 90A and yard lights 90B.

The circuit board 250 is diagrammatically depicted in FIG. 13, and isconnected to the line voltage connectors 242 and 244, attached to theterminal block connector 240. The neutral bus 246 is attached to theterminal block, and a neutral connection 246A is made to the circuitboard. The neutral (white) conductor 60B3 from the 240 VAC, 50A serviceis connected to the neutral bus. The ground (green) conductor 60B4 fromthe 50A service is connected to a ground bus 248 attached to the metalcabinet 110. The board 250 includes printed wiring conductor patternswhich connect the various circuit devices mounted on the board and theconnector terminals.

The board 250 is supported on the metal cabinet 110, and ground isconnected through metal threaded fasteners 258 (FIGS. 10-12) whichsecure the board in place. Extending from the sidewall partitions 110Hand 110G are metal brackets comprising shelf portions 110L and 110N,supported by metal leg portions 110M and 110P, respectively. Thefasteners 258 secure the board 250 to the shelf portions. Thus, theboard is physically connected to the cabinet 110 by four threadedfasteners 258, and to the terminal block 240 by four threaded fasteners251, in this exemplary embodiment. This attachment technique facilitatesthe installation and removal of the board 250 relative to the cabinet.Of course, other types of removable fastener structure couldalternatively be employed instead of screw fasteners, including clamps,spring clips, friction connectors, and the like.

The exemplary installation illustrated in FIG. 13 includes two 240 VACloads, the spa jet pump 86 and the filter pump 80. These loads areconnected to 240 VAC service through a 240 VAC connector 260 comprisinga first connector structure 260A (FIG. 10) mounted on the top surface ofthe circuit board, and a removable connector structure 260B (FIG. 13) towhich insulated conductors or wires are connected running to the loads.The respective connector structures have respective pins andcorresponding plug receptacles which mate together when the connectorstructure are mated. Such connectors are well known; a suitableconnector is the connector marketed by RIA Electronics, Inc., Etherton,N.J., as mating parts 31041208 (pin connector) and 31007208 (plugconnector). Use of this type of connector structure facilitates fieldwiring of the line voltage loads.

Respective terminals of the connector structure 260A are electricallyconnected to printed wiring trace 252 running to the connector 242, andother connections to other terminals of the connector structure 260A aremade through switching relays and fuses to wiring trace 254 to theconnector 244. By appropriate connection to respective terminals of theconnector structure, 240V service is available. Insulated conductor 86Ais connected to a “red” terminal connection, i.e. a connection which iselectrically connected to connector 242, to which the red conductor ofthe 240V service is connected. Conductor 86B is connected to a “black”terminal connection, i.e. a connection which is electrically connectedthrough a relay and fuse to connector 244, to which the black conductorof the 240V service is connected. Conductor 86C connects the ground bus248 to the spa jet pump.

Similar connections are made to the filter pump 80 to provide 240Vservice. Thus, wire 80A is connected to another “red” terminalconnection on connector 260B, wire 80B is connected to a “black”terminal connection on connector 260B, and wire 80C connects the groundbus 248 to the filter pump.

The 240 VAC loads are controlled by respective switch devices, e.g.non-latching relays, in turn controlled by the system controller. Eachload circuit is also protected from excessive current draw by a fusedevice. Thus, the spa jet pump is controlled by relay 280 and circuitprotection is provided by fuse 286, respectively mounted on the circuitboard 250. To accomplish this, a series circuit connection is madebetween the circuit trace 254, relay 280 and fuse 286 to thecorresponding terminal on connector structure 260A, using solderconnections to wiring traces formed as part of the board 250. The filterpump 80 is controlled by relay 282 and circuit protection is provided byfuse 288. A spare 240V service circuit is provided, with relay 284 andfuse 290.

The circuit board 250 further has a 120V service connector 270, alsocomprising a fixed connector structure 270A mounted to the board, and aremovable connector structure 270B (FIG. 13) connectable to the fixedconnector structure. These connector structures can be implemented inthe same manner as the connector structures 260A and 260B, furtherfacilitating field wiring of the controller system. Insulated wiresrunning to the load devices are attached to the removable connectorstructure 270B. Respective terminals of the connector structure 270A areelectrically connected via wiring traces of the circuit board to the redconnector 242, the black connector 244 and the neutral connector 272 inturn connected to the neutral bus 246 via wire 246A. Thus, 120V serviceof either phase (red or black) is available at the connector 270. Theheater 78 is wired to the connector 270 by wires 78A, 78B. When thecontroller system calls for heat, 120 VAC power to activate the heateris supplied, which enables all ignition and temperature regulatingfunctions of the heater. The heater in turn ignites gas supplied to itsinternal gas valve and burner, heating the water which is flowing fromthe pump and filter. The spa light circuit 90A are connected to a blackpolarity connection at connector 270 by wire 90AA, and to the neutralbus 246 by wire 90AB. The yard lights 90B are connected to a redpolarity connection at connector 270 by wire 90BA, and to the neutralbus 246 by wire 90BB. Provision is made for an optional 120V load device238, which can be connected to connector 270 by wire 238A, and to theneutral bus 246 by wire 238B.

Each 120 VAC circuit connected through the connector 270 is controlledby a switch device actuated by the controller 402, with circuitprotection provided by a corresponding fuse, respectively mounted on thecircuit board 250. The switch device and a corresponding fuse areconnected in series between a corresponding line voltage wiring trace(i.e., black, red, white) and a terminal of the connector 270. Theheater is controlled by relay 300, with circuit protection provided byfuse 292. The optional load 238 is controlled by relay 302 and protectedby fuse 294. The yard light circuit 90B is controlled by relay 304, andprotected by fuse 296. The spa light circuit 90A is controlled by relay306, and protected by fuse 298.

The various electrically-powered components controlled and poweredthrough the pool control system can give rise to power load issues,where the total current available through the pool control system couldbe insufficient to meet all load conditions. To provide power to the120V lighting 90, two different 120V light circuits 90A and 90B arehardwired on the control board. One circuit, say 90A, is powered byconnection to the black and white conductors of the 240 AC service. Thesecond circuit is powered by connection to red and white conductors ofthe 240 VAC service, thus using a different phase of the 240 VACservice. With this arrangement, even though both circuits each draw upto 10 Amps at 120 VAC, the total power rating for both circuits is 10Amps at 240 VAC.

This feature of the invention is described with respect to thesimplified schematic of FIG. 21. The rating of a 50 Amp 240 VAC circuitin the United States is achieved with two 120 VAC waveforms, which are180 degrees out of phase. Thus, consider the node RAC (which could beconnected to the red conductor of the 50 Amp service) to be at +120VAC,and the node BLAC (which could be connected to the black conductor ofthe 50 Amp service) to be at −120 VAC. The voltage difference betweenthe two nodes is thus the 240 VAC service, and the load L1 is a 240 VACload. Current can flow through the load L1 to a maximum of 50 Amps inthis 50 Amp circuit. However, if the total current through the load L1is less than 50 Amps, the balance can be directed through loads L2 andL3, connected between RAC and the neutral conductor, and between BLACand the neutral conductor, respectively. Loads L2 and L3 may or may notbe equal, and the return path is through the neutral conductor, unusedif all 50 Amps is not passed through the load L1. However, the totalcurrent passing through plane P-P is always 50 Amp. When loads L2 and L3are equal, they act as virtual grounds for each other, and no currentflows through the neutral leg. If these loads are unbalanced, thedifference flows in the neutral leg to make up the 50 Amp current.

The system 100 further includes a transformer coupled to the 120V AC toprovide low voltage DC power at 5V and 15V to provide power to theelectronic components including the controller, and to operate the lowvoltage load devices, such as the valves 70, 72. The transformer isconnected to the circuit board 250 to receive input 120V AC, and toprovide the low voltage AC and DC supply voltage levels.

To further facilitate field wiring of the controller system 100, theservice control panel 112, the control panel 102 and the spa controlpanel 104, the sensors, and the low voltage loads such as the valves,are connected to the circuit board 250 by low voltage cables andmodular, telephone-jack-type connectors. In this way, the low voltagecables can be connected or disconnected easily by simply detachingremovable connector portions from corresponding connector portionsmounted on the board. Thus, referring to FIG. 13, for example, thecontrol panel 102 is connected to the board 20 by a low voltage,multiple conductor cable 102D and a modular connector 102E having a maleportion connected to the cable end and a female portion mounted to theboard 250. The male portion is latched in place in the female portion,making electrical contact with the respective conductors, and can bedetached by pressing a plastic latch tab and pulling the male portionaway. Similar connections are made to the spa panel 104 and the servicepanel 112, through respective cables 104C, 112C and modular connectors104D, 112D. Modular board connectors suitable for the purpose arecommercially available, e.g. the telephone/data type connectors marketedby Berg as part numbers 93899-001 (6 position board connector) and69255-001 (eight position board connector). The mating male connectorstructures attached to the cabling are also commercially available.

Similarly, the sensors and low voltage loads are also connected to theboards using modular connectors. The leads for these devices areconnected to male connector structures, which are mated to respectivefemale connector structure mounted on the board. For example, the wiringfor valve 70 is connected to the board by modular connector structure70A, and the wiring for sensor 204 is connected to the board by modularconnector 204A. Suitable connector structures for sensor connector 70Ainclude the Molex part numbers 705-43-0106 (board connector structure)and 14-56-8022 (wire connector structure). Suitable connector structuresfor valve wiring connectors include JST part numbers JST-32B-XH-4 (boardconnector structure) and JST-02NR-E2R (wire connector structure).

The low voltage cabling for the control panels is routed from the mainbay 110F of the control cabinet, through window opening 110H1 formed insidewall 110H and into the low voltage secondary bay 110K of thecabinet, as shown in FIG. 10. The cable 112D can be connected to thepanel 112 on the front cover, and the cables 102D, 104D can be passedthrough service opening(s) formed in the bottom wall 110B of the cabinetand then routed to the respective panels 102 and 104. Similarly, the lowvoltage wiring for the low voltage loads is passed from the main bay110F through window 110G1 of sidewall 110G into the right low voltagesecondary bay 110J, and then routed through service opening(s) formed inthe bottom wall 110B of the cabinet for routing to the low voltage loadsand sensors.

An aspect of this invention is the use of a controller system which isreadily field wired, providing significant saving in installation labor.The board 250 can be removed from the cabinet 110 easily, withoutdisconnecting the line voltage conductors 60B1-60B4. This isaccomplished by removing the fasteners 258 which secure the board to thecabinet, removing the fasteners 251 which connect the board to theterminal block 240, and disconnecting the line voltage and low voltageconnectors. This can be done in a matter of minutes, and thusfacilitates servicing the system 100. If a board 250 is malfunctioning,it is a simple matter to remove it for repair or replacement in thefield. Moreover, because the line voltage conductors 60B1-60B4 need notbe physically disconnected, the safety hazards involved in such work arereduced.

In an exemplary embodiment, the controller system 100 includes amicroprocessor 402 such as a Pic 16C65A CMOS microcomputer marketed byMicrochip, which accepts information from a variety of sensors and actson the information, thereby operating according to instructionsdescribed more fully in FIGS. 14A-14F. The invention is not limited tothe use of a controller including a microcomputer or microprocessor,whose functions can instead be performed by other circuitry, including,by way of example only, an ASIC, or by discrete logic circuitry.

An exemplary main operational routine 700 illustrating the programmedoperation of the microprocessor 402 is shown in FIG. 14A. After systempowerup (702), a “check GFCI” subroutine 704 is performed. Thissubroutine has for its purpose to electronically test whether the GFCI62 is properly operational, and is described more fully with respect toFIGS. 14B and 15. Upon successful completion of GFCI test, the mainprogram is run (706). The main program performs the control functionsneeded for running the various pool and spa functions, including runningthe heater and pump. The primary function of the main program is tomonitor safety issues, such as over-temperature conditions. Thus, themain program will manage water temperature in the pool and spa. Otherfunctions performed in the main program are to monitor the clock andreal time to determine when to activate features, e.g. lights, heater,and the like in accordance with a programmed time schedule. Themicroprocessor is user-programmable to set up the schedule. U.S. Pat.Nos. 5,361,265 and 5,559,720 describe techniques for programmingmicroprocessors in a spa environment.

The routine 700 performs an interrupt (708) of the main program every 16milliseconds in this embodiment. As part of the interrupt routine, thesystem time, kept by an incremental timer, is incremented (710) byadding one to the internal stack of the counter, and the control panelbuttons are checked (712) to see for activation. If none of the buttonshave been pressed or otherwise activated, operation returns (714) to themain program at the point of interrupt. If any control panel switcheshave been activated, then the panel service subroutine 716 is entered.This panel service subroutine activates features, and accepts and inputsand alarms entered via panel switches. The panel push-button impulse,generated by the electronic panel circuitry, is several hundredmilliseconds long. Since the interrupt is every cycle of the line powersupply, or approximately every 16 milliseconds, the processor has ampletime to detect a button push and respond accordingly. The processorloads the data represented by a button push, and loads that data into aregister. This register is then accessed by the microcomputer every fewmilliseconds and appropriate action is taken. After completion of thepanel service subroutine, the emergency disconnect routine is entered(718), and thereafter operation returns (714) to the main program to thepoint of interrupt.

The GFCI test routine 704 is described further with respect to FIGS. 14Band 15. According to this aspect of the invention, the system 100 willtest for proper connection and operation of the GFCI 62. This is done inthe exemplary embodiment by inducing a ground fault shortly after powerup of the system, and then looking for GFCI interrupt within a specificshort time. If this does not occur, the controller 100 will display atype of “GFCI absent” message and accept no further inputs from thecontrol panels, preventing further operation of the system 50. If aninterrupt does occur, this event will be stored in a nonvolatile memoryas a flag. Then, when the system is re-powered up, the stored flaginformation will be read, the system will know a GFCI is installed, andthe system 100 will operate normally.

Thus, when the system 100 is powered up the first time afterinstallation, it will wait a short time, say five seconds to tenseconds, and conduct a GFCI test to determine whether the GFCI 62 isoperational. FIG. 15 illustrates schematically circuit elements employedfor this test. The GFCI 62 is a well known apparatus, and includes sensecoil 62A, relay 62B and control circuit 62C. The sense coil 62A iscoupled to conductors of the 50 Amp service 60A. In the event of acurrent imbalance between the incoming and outgoing current in the linevoltage service, the control circuit will sense this condition throughcoil 62A, and open the relay 62B, interrupting power. The function of aGFCI is well known in the art.

The controller 100 includes a voltage transformer circuit 480 willtransforms the 120 VAC input line voltage to a 12 VAC level. This 12 VACis applied to a voltage divider, and the sinusoidal divider voltagedrives the input to gate 484, which converts the sinusoidal input signalto a square wave signal between 0 V and +5 V. The microprocessormonitors the square wave signal, and will sense nulls in the powerwaveform to switch the relays at zero crossings in the power waveform tominimize arcing in the relays.

An output port of the microprocessor 402 is coupled to a relay 358. Oneswitched port of the relay is connected at node 368 to one 120 VAC wire;the other switched port is connected to earth ground. A power supply 406provides a dc power supply voltage from the line voltage transformer topower the microprocessor. Also connected to the microprocessor is anonvolatile random access memory (RAM), e.g. an EEPROM memory 404.

The GFCI test is performed by the microprocessor 402 providing a controlsignal to turn on transistor 405, closing the relay switch 358B andshorting the line voltage at node 368 to earth ground through a 10 Kohmresistor 362. This will create an imbalance in the power supply lines60A1 and 60A2. If the GFCI 62 is present and properly connected, theGFCI relay switch 62B will be opened, interrupting power to thetransformer 480. The microprocessor 402 will sense this condition,through its monitoring of the gate 482 output, and in response to lackof a square wave signal will store a flag bit in the EEPROM 404. Thiswill occur before the microprocessor loses power. The next time thesystem 100 is powered up, the startup program routine will look for thisbit, and if set will proceed to execute the main program. However, ifthe flag is not set, the GFCI test will be performed.

The GFCI 62 must open the circuit within a certain time period after ashort or imbalance is detected. For example, for a Class A GFCI, therated time period is 7 milliseconds, and for a Class B GFCI the ratedtime period is 20 milliseconds. Therefore, there must be a start timefor the test and a finite period of time after the relay 358 is closedto indicate a successful test. Because each cycle of the 60 cycle linevoltage supply is 16 milliseconds long, the microprocessor must wait acertain time period, time A, before closing relay 358. The signal inputfor the start of the time period A is the square wave from gate 482,connected to the transformer 480, which generates an AC signalproportional to the line voltage supply, but isolated from the linevoltage supply.

The time period A can vary from 1 millisecond to 15 milliseconds in thisembodiment. Time interval B is the time period before checking foranother input from the gate, i.e. a rising edge or high state on thesquare wave signal. Time interval B can vary from 1 millisecond toseveral hundred milliseconds, but will generally not exceed 100milliseconds.

When the microprocessor 402 has begun the time B countdown, it looks forone input on the gate waveform. If it continues to see rising or highinputs on the gate waveform, indicating that the GFCI relay has notopened, the microprocessor will wait the entire time B, and then branchto a lockout program. This program will set an error message to the maincontrol display panel such as “GFCI FAIL,” and stop further input oroperation.

If there is a power shutdown during this wait time B, the microprocessorwill write a flag bit to the memory 404, to indicate a successful test.As the power to the microprocessor is shut off, a short term powersupply back supply, shown schematically as capacitor 408 and resistor410, will give the microprocessor 402 sufficient time to finish the waittime B, and set the GFCI flag in the memory 404 before shutdown.

FIG. 14B shows the GFCI subroutine 704 in further detail. After systempowerup at 702, the GFCI flag bit memory location in the memory 404 ischecked (704A), and if set, operation returns to the main program(704B). If the bit is not set, then at 704C, the microprocessor monitorsthe gate output to detect a rising input from the gate. Once this isdetected, after a wait of time interval A, the relay 358 is closed(704D). Now the microprocessor waits for time interval B (704E), andthen checks for a rising input from the gate (704F). If a rising inputis not detected, then the GFCI flag bit is set (704G), and the system100 will shut down. If a rising input is detected, indicated that thepower was not interrupted, then a “GFCI FAIL” message is displayed(704H), and the system is locked (704I), preventing further operation orinput. Typically, all functions are disconnected or disabled, except thewater pump, which is needed for freeze protection.

An aspect of the invention is to integrate with the pool controllersystem 100 the circuitry or logic necessary to respond to user commandsto activate the fill valve 76 to dispense water into the pool from thewater line. The controller is responsive to a manual control panelselection by the user to actuate the fill valve, say by actuation ofpanel button 102B1 (FIG. 4), and release water into the pool toreplenish the water. The controller starts an internal timer, and thenafter a predetermined timer interval elapses, or a time desired by theuser, shuts off the valve to stop filling the pool with water. This willaddress the problem of the pool owner manually turning on a fill valve,and then forgetting to later turn off the valve. Alternatively, a waterlevel sensor detects a low water level condition, and automaticallyactivates the fill valve for a predetermined time interval. As anadditional optional protection against overfilling, the water levelsensor can sense an overfill level, and provide a signal to thecontroller indicative of this condition. The controller acts on theoverfill signal to close the fill valve, even though the predeterminedtimer interval has not elapsed.

The pool fill feature is illustrated in the flow diagram of FIG. 14C.During an interrupt (708) from the main program, the “activate features”subroutine 718 is entered. One of the features is the “pool fill”feature; of course there can be other features activated during thisinterrupt, not pertinent to the fill routine. If the user enters a poolfill command through one of the control panels, by activating one of thepanel switches, for example, then the pool fill feature is selected(718A). If the pool fill feature is not selected, operation returns tothe main program, or to another feature. At 718B, the fill time isselected. The user can enter this data through the control panel, e.g.in increments of minutes, or a default fill time can be used, e.g. 30minutes. In the later event, operation can proceed from step 718Aimmediately to step 718C, to open the valve. Otherwise, the time is set,and then the valve is opened, with the microprocessor starting a timerfor timing out the selected or default fill time interval. At thispoint, operation returns to the main program.

A function of the main program 706 is to monitor the fill activity oncestarted. Thus, at periodic step 718D, a check will be made for thestatus that a fill has already been activated. If not, operation returnsto the main program. If a fill operation has been started, the timer ischecked at step 718E. If the fill time has not expired, operationreturns to the main program. If the fill time has expired at 718E, thefill valve is closed (718F), and operation returns to the main program.

Another feature is the use of a water level sensor for detecting whetherthe pool water level has reached a low level, at which water should beadded. Thus, during subroutine 720, for accepting sensor inputs andalarms, the water level sensor 224 is checked at 720A. If the waterlevel is above the low level, operation returns to the main program. Ifthe pool level is at the low level, the pool fill valve 74 is opened,and operation returns to the main program. The pool fill valve can besubsequently closed when the water level sensor probe again makescontact with water. Alternatively, the processor can be programmed toclose the valve a predetermined time interval after it is opened, sayone hour. Also, the overfill condition can be sensed, and thisinformation triggers closing the fill valve even though the timeinterval has not yet elapsed.

Another aspect of the invention is an emergency disconnect switch forthe pool/spa, implemented without the need for bringing line voltage tothe emergency disconnect switch, but rather using low voltage signalsand the intelligence of the spa controller 100. The emergency disconnectswitch when closed will cause a grounding resistor to be connectedbetween the earth ground line and line voltage, inducing a ground faultwhich will be detected by the GFCI 62, thus providing a level ofredundancy.

This feature is illustrated in FIG. 16. The emergency disconnect switch350 is on a housing 352, which is mounted near the spa, to be accessiblein the event of a need to immediately shut down the pool/spa equipmentpowered by line voltage through the system 100. Conductor wires 354, 356run between the circuit board 250 of the controller system 100 andrespective terminals of the normally open switch 350. The wire 354 isconnected to one terminal of the coil 358A of a relay 358 on the circuitboard 250; the other terminal of the relay coil is connected to a 15Vsupply. The relay switch 358B is connected between earth ground andthrough a 10 Kohm resistor 362 to one phase of the line voltage service,e.g. the black 120 VAC line, at node 368. The other terminal of theswitch 350 is connected to wire 356, which is connected to node 362 atthe board 250. A 50 Kohm resistor is mounted in the housing 352 betweenthe wires 354 and 356, and in parallel with the switch 350. A 10 Kohmresistor 366 is connected from node 362 to ground, forming a voltagedivider with the resistor 360. An analog-to-digital converter (ADC) 364is also connected to node 362 on the circuit board 250, and provides adigital voltage value to the system controller 402 mounted on the board250.

The closing of the emergency stop switch 350 will close the relay switch358B, connecting the 120VAC black line voltage at node 368 throughresistor 362 to earth ground. This is a ground fault, which is detectedby GFCI circuit 62, and which is tripped, interrupting line voltageservice to the pool controller and power distribution system 100. Thus,all power to system 100 will be interrupted. As a redundant powerdisconnect feature, the voltage at the voltage divider node 362 ismonitored through the ADC 364 by the controller 402 under normaloperating conditions. If the switch 350 is closed, the resistor 360 isbypassed, and the voltage at node 362 read by the ADC changes. Thecontroller 402 detects this condition, and immediately opens the relaysproviding line voltage to all line voltage loads. Thus, even if the GFCI62 were to fail, and therefore not interrupt line voltage service tosystem 100, the controller 402 would take action to open shut down theline voltage loads.

The controller 402 can also detect that the emergency disconnect switch350 is not properly installed. In this case node 362 will be at an opencircuit voltage condition. The controller 402 monitors the voltage atnode 362, and if an open condition is detected, this is recognized as anerror or fault condition. The controller can then prevent operation ofthe system 100, prevent line voltage from being connected to the linevoltage loads, or take other action needed to address the lack of properconnection of the stop switch, such as providing an error message on thecontrol panel display.

FIG. 14D illustrates the “ESTOP disconnect” subroutine 722 (FIG. 15) infurther detail, wherein the emergency stop switch 350 is monitored. At722A, a check is made to determine whether this feature is enabled, andif not, operation returns to the main program (722G). If the feature isenabled, then the microprocessor 402 reads the voltage at node 362through the ADC 364. If a value indicating the presence of the switchand resistor 360 is not read, an error message is displayed on thecontrol panel (722C) and operation returns to the main program. If themicroprocessor senses that the emergency switch system is installed,then at step 722E, if the voltage at node 362 indicates that the switch350 is closed, then all line voltage loads and features are shut down(722F), and the controller 100 will wait for power off and reset. If theswitch 350 is not closed, operation returns to the main program (722G).

When the pool filter becomes clogged, the filter pressure rises. Asshown in FIG. 1, filter pressure sensors 208A and 208B are mounted inthe filter inlet and outlet lines 9 and 10 to monitor the back pressure,i.e. the difference between the input water pressure and the outputwater pressure, and when it reaches a certain level, the controllercauses a warning or error signal to be displayed on the control panel,such as “Back Flush the Filter” or “Clean Filter.”

Another aspect of this invention is the monitoring of the natural gassupply pressure to the pool heater system. A gas pressure sensor 224 isplaced in the gas line to the pool heater 78 to monitor gas pressure.The sensor includes a sending unit which provides a gas pressure signal.Pressure sensors suitable for the purpose are commercially available;one exemplary sensor is marketed by Omega Engineering Inc., Stamford,CT, as the 30 PSI sensor device, PX182-030-GI. This signal is providedto the controller 402, which is programmed to provide an error messageon the display of control panel 102 when pressure reaches a minimumthreshold, and also prevents the heater from operating.

The gas pressure and backpressure monitoring features are furtherillustrated in the flow diagram of FIG. 14E. The subroutine 720 (“acceptinput and alarms”) further includes step 720C, wherein themicroprocessor receives as data inputs the gas pressure value, the inputwater pressure (IP) to the filter, and the output water pressure (OP)from the filter. At step 720D, if the gas pressure is below thepredetermined low threshold value, the heater is disabled and an errormessage is sent to the panel display (720E). If the filter backpressure(i.e., the difference between the input pressure and the outputpressure) exceeds a predetermined threshold value (720F), an alertmessage is sent to the panel display to indicate that the filter shouldbe cleaned (722N).

FIG. 14F illustrates additional steps which can be included in the“accept inputs and alarms” subroutine 720. Sensors 218 and 216respectively detect the condition that the pool cover is open or thegate to the pool area is open. The sensors can be Hall effect switches,or other types of switching devices, as will be apparent to thoseskilled in the art. The sensor outputs are connected to the controller402, which is programmed to interpret the outputs as potential alarmconditions, and generates an audible warning signal using alarm soundspeaker or siren 96 (FIG. 6) or another warning signal such as a visiblemessage on a panel display, indicating that the pool gate or cover isopen. Thus, at step 720I, the subroutine checks to see whether an alarmsignal has been input from a sensor such as the gate open sensor 218 orthe pool cover alarm 224. If not, operation returns to the main program(or to other aspects of this subroutine). If an alarm has been received,then an alarm output is activated by the controller 402, which caninitiate an audible and/or visible warning message.

An improvement in production is obtained by use of anin-circuit-programmable microcontroller. This microcomputer can beprogrammed by sending suitable signals to an appropriately configuredinput circuit after the microcomputer has been installed via solderconnections onto the circuit board 250. This improved productiontechnique includes the steps of (i) soldering the microcomputer into acircuit board configured for in-circuit programming; (ii) connecting theboard to a programmer device using electrical leads, in accordance withthe manufacturer's instructions; (iii) loading the program into themicrocomputer from the programmer; (iv) power up the circuit board inaccordance with normal operating procedures; and (v) verify the properfunctioning of the circuit board with the microcomputer. Operation isverified in this embodiment by powering up the board and performing anoperational clock, either manually or by a suitable computer testsystem.

Temperature sensors that are known in the art utilize a singlethermistor sealed inside a case for sensing water temperature, highlimit temperatures in a heater, and air temperatures. To facilitateredundancy in these critical components, two thermistors are installedinside one housing. This moderate increase in cost doubles thereliability of a very reliable technology, and removes the need for amore expensive option of dual sensor assemblies dedicated to a singletemperature value.

FIGS. 17-19 illustrate temperature sensor 202 in further detail.Temperature sensors 204 and 206 can have the same circuitry andstructure as sensor 202, and so will not be described further. FIG. 17is a circuit diagram of the sensor 202, which includes two solid statetemperature sensing devices 202B, 202C, one terminal of each connectedto wiring 202A at node 202D. The solid state temperature sensing devicescan be implemented by various devices, including thermistors,thermocouples, temperature-sensing diodes wherein leakage currents aretemperature-dependent, or constant current source circuits wherein thecurrent is temperature-dependent. An end of the wiring 202A is connectedto the controller circuit board 250 at connector 410. The wiring 202A isconnected to a +5VDC supply node 412. The second terminal of thermistor202B is connected by wiring 202E, through the connector 412 to oneterminal of resistor 414, connected to ground. The second terminal ofthermistor 202C is connected by wiring 202F to resistor 416, alsoconnected to ground. The resistors 202B and 414 thus form a voltagedivider circuit, with the voltage at node 420 dependent on the variableresistance of the thermistor. Similarly, resistors 202C and 416 providea voltage divider circuit, with the voltage at node 418 dependent on thevariable resistance of the thermistor. The voltages at nodes 418 and 420are converted to digital values by ADC 364 and monitored by thecontroller 402. Since the resistance values of the thermistors varyprecisely with their temperatures, two temperature readings are providedby the sensor 202. The temperature values can be averaged, and in theevent of anomalous readings from one or the other thermistor, theanomalous value can be discarded. This temperature sensor providesimproved reliability through this redundancy.

An improved assembly technique is also used in the fabrication of thesensor 202. Referring now to FIGS. 19 and 19, the sensor includes adielectric substrate or circuit board 202G. A distal end 202H of thesubstrate has two notches 202I, 202J formed therein. The respectivethermistors 202B, 202C are supported in the notches of the board. FIG.18 is a diagrammatic view showing one side of the board 202G; FIG. 19shows the reverse side of the board.

The sensor 202 further includes a metal tubular housing 202K having aclosed end 202L and an open end 202M. A collared sleeve 202N is used, incombination with the length of the sensor circuit board 202G, toprecisely control the depth of insertion of the circuit board into thehousing prior to potting with an epoxy. This eliminates the problem ofimprecise circuit board placement, which can lead to disparities insensed temperatures between sensor units. The sleeve 202N has an openingformed therein through which the wiring leads 202A, 202E and 202F arebrought out. In this embodiment, the sleeve is a plastic molded partwith a distal end which contacts the circuit board 202G, and a collar202O is larger in diameter than the diameter of the housing 202K, thusproviding a stop surface against which the open end of the housing isbrought into contact during assembly. Of course, other arrangementscould alternatively be employed to provide a circuit arrangement whichis self-registering in insertion depth within the housing. Theself-registering feature of the temperature sensor can alternatively beemployed with sensors using a single sensing element, such as a singlethermistor.

FIGS. 20A-20C illustrate an exemplary circuit schematic for the circuitboard 250. Various sensor inputs to the controller are passed throughsignal conditioning circuitry and then to the ADC 364 (FIG. 20A). Thus,for example, air temperature sensor 202 is shown as a two wire device,e.g. with a single thermistor sensor, connected to the signalconditioning circuitry indicated as 203, although it is contemplatedthat an improved sensor as shown in FIGS. 17-19 will alternatively beemployed. The improved sensor will utilize two multiplexed inputs to theADC, so that each circuit can be read by the controller 402. The outputof the signal conditioning circuitry is passed to the ADC 364, which canprocess several inputs through a multiplexing arrangement. Illustrativesensor devices 204, 206, 210, 212 are similarly connected through signalconditioning circuitry to the ADC. Other sensor devices, e.g. the gatesensor 218, may have signal levels at appropriate logic levels, and somay not require the same signal conditioning in order for the ADC tohave a desired signal level to convert to digital form. Circuitry forinterfacing sensor devices to a microcomputer through an ADC are wellknown in the microprocessor arts.

A crystal oscillator clock circuit 320 provides clock signals for themicrocomputer.

The circuit board assembly 250 also includes a power supply 322 (FIG.20A), which converts the line voltage service into 24 VAC for providingpower to the water valves, and into 15 VDC, 12 VDC and 5 VDC forproviding DC power needs of the controller board assembly, such as relaypower and a regulated DC supply for the microcomputer 402.

The microprocessor 402 controls the line voltage loads and low voltageloads through output drivers 320 and 322, which in this exemplaryembodiment are Darlington drivers which convert the logic level outputsignals from the microprocessor into the necessary drive signals forcontrolling the relays and switches which operate the line voltage loadsand the low voltage loads, such as the valves. Exemplary circuitry isillustrated for operating exemplary line voltage loads, including theheater 78 (FIG. 20C) and pump 80 (FIG. 20B). Exemplary circuitry isfurther illustrated for operating the low voltage loads, e.g. the fillvalve 76 (FIG. 20B), and valve 74 (FIG. 20C). In this embodiment, thelighting circuits 90A and 90B are controlled through triac switches.Exemplary circuitry is illustrated for operating lighting circuit 90B,by use of triac circuit 306 which is in turn driven by the driver 332(FIG. 20C).

A set 402A of wiring connections running to programming pins of themicrocomputer 402 is made available for connection to the programmerdevice used for in-circuit programming as described above.

The microprocessor 402 further interfaces with the control panels 102,104 and 112 through an interface 338 and support circuit 336. Theinterface supplies panel power at 5 VDC, and power at 12 VDC and 24 VACfor panel lighting functions. Data output, data input and clock signalsare provided on lines 342, 344 and 346, respectively. The interfaceprovides three separate connector interfaces, one connector for eachpanel, so that the panels are connected to the circuit board assemblythrough respective detachable connector devices.

It is understood that the above-described embodiments are merelyillustrative of the possible specific embodiments which may representprinciples of the present invention. Other arrangements may readily bedevised in accordance with these principles by those skilled in the artwithout departing from the scope and spirit of the invention.

1-53. (canceled)
 54. A bathing installation control system, comprising:a plurality of electrically powered devices associated with operation ofthe bathing installation; a microprocessor-based controller systemoperatively connected to the plurality of electrically powered devicesfor controlling the operation of said devices; a ground fault circuitinterrupter (GFCI) circuit; a line voltage service connected to thecontroller system and the plurality of electrically powered devicesthrough the GFCI circuit, the GFCI circuit adapted to detect groundfaults and interrupt the line voltage service to the controller systemand the plurality of electrically powered devices upon detection of aground fault; a fault inducing circuit for selectively inducing a groundfault condition between line voltage and ground in response to anelectronic command signal; a circuit actuation system responsive to anerror or fault condition, the test circuit actuation system connected tosaid controller and said fault inducing circuit, the circuit actuationsystem adapted to actuate the fault inducing circuit to induce a groundfault between line voltage and ground in response to the error or faultcondition, thereby tripping the GFCI circuit and disconnecting the linevoltage service from said plurality of electrically powered devices andsaid controller system.
 55. The system of claim 54, wherein the circuitactuation system includes a manually operated switch accessible to auser of the bathing installation.
 56. The system of claim 55, whereinthe error or fault condition includes the condition that the circuitactuation system is not properly installed in said system.
 57. Thesystem of claim 54, further comprising a plurality of switches each forselectively connecting one of said plurality of devices to said linevoltage, the plurality of switches controlled by said controller system,and wherein the controller system is responsive to the circuit actuationsystem to command said plurality of switches to disconnect the pluralityof devices from said line voltage in the event the circuit actuationsystem actuates the fault inducing circuit and said GFCI circuit failsto disconnect said line voltage service from said controller system andsaid plurality of devices.
 58. The system of claim 57, wherein saidplurality of switches each comprises a relay switch.
 59. The system ofclaim 54, wherein the circuit actuation system includes an algorithmperformed by said microprocessor-based controller system and adapted tocause the controller system to generate said electronic command signalin response to an algorithmically-determined fault or error condition.60. The system of claim 59, wherein said algorithmically-determinedfault or error condition includes a decision to conduct a GFCI circuittest.
 61. The system of claim 54, wherein the bathing installation is apool or spa installation.
 62. The system of claim 54, wherein theplurality of electrically powered devices includes a water pump forcirculating bathing water through a circulating water path, and abathing water heater.